I use small pieces of lump strategically placed throughout the snake.
@1buckie put me on to this, and I believe he used the term
burn assurance, or
burn insurance.
As already mentioned, the dome therm will be different from the grate temp.
With all that said, I don't do the snake much in the cold weather … Mainly due to wind …
Or, the amount of meat I was cooking was a lot and was not done at the time that I was hoping …
Either way, keep at it, or try other methods in the cold weather.